Selective Power Management in IEEE 802.11 infrastructure WLANs

In IEEE 802.11 infrastructure LANs with Distributed Coordination Function (DCF), the power saving algorithm works as follows: the stations with no frames to transmit may switch to the doze mode to save power; all these stations are informed by the Access Point (AP) at the beginning of each beacon interval if there are pending frames; these stations then start contending the channel to receive these pending frames from the AP, if any. In this work, we propose a different strategy based on giving the AP the power of deciding which stations with pending frames to notify. Indeed, there are several circumstances with high channel traffic in which it is better to defer the transmission so as to reduce the expected energy consumption. The reduction in energy consumption is obtained at the expense of an increase in the transmission latency. The AP notification decision is then taken in view of the total average energy consumption and the introduced latency. Simulations have shown that the performance of the proposed method may lead to an overall energy saving of about 63% respect to the standard algorithm.